论文标题
确保LSB嵌入结构性稳定分析
Securing LSB embedding against structural steganalysis
论文作者
论文摘要
这项工作探讨了通过在消息嵌入之前修改封面图像统计信息，可以使LSB嵌入可以安全地防止结构性地分解。自然图像具有通过某些$ k $连续像素的某些集合的基础性表达的对称性。 LSB嵌入打扰此余额和$ k^{\ rm th} $ - 订购结构攻击会导致存在的隐藏消息的存在与$ k $ Tuplass的集合中的不平衡大小成比例。为了防止$ k^{\ rm th} $ - 订购结构攻击，覆盖修改涉及在不同集合中$ k $ tuplace的重新分布，以使封面图像的对称性破裂，然后通过LSB嵌入的ACT修复，以使Stepego图像带有原始封面的统计数据。为了防止所有订单$ k $的订单，必须保留$ n $ tuples的统计数据，而$ n $是所有订单中最不常见的倍数$ \ leq k $。我们发现，这仅是可行的，因为可确保高达$ 3^{\ rm rd} $ - 订单攻击（示例对和三元分析），因为高阶保护几乎导致嵌入能力为零。确保$ 3^{\ rm rd} $ - 需要重新分配二次的内容：而不是执行这些$ 6^{\ rm th} $ - 订单覆盖覆盖的修改，这导致嵌入能力很小，我们将问题减少到三胞胎中的问题，以保留统计学的统计信息。这是通过仅嵌入每个Sextuplet的某些像素来完成的，将最大嵌入率限制为$ \ leq 2/3 $每个通道。在各种图像格式上进行测试，我们报告了JPEG压缩图像的最佳性能，平均最大嵌入率不可检测到$ 2^{\ rm nd} $ - 和$ 3^{\ rm RD} $ - 订单攻击每通道0.21位。
This work explores the extent to which LSB embedding can be made secure against structural steganalysis through a modification of cover image statistics prior to message embedding. Natural images possess symmetries that are expressed through approximately equal cardinalities of certain sets of $k$-tuples of consecutive pixels. LSB embedding disturbs this balance and a $k^{\rm th}$-order structural attack infers the presence of a hidden message with a length in proportion to the size of the imbalance amongst sets of $k$-tuples. To protect against $k^{\rm th}$-order structural attacks, cover modifications involve the redistribution of $k$-tuples among the different sets so that symmetries of the cover image are broken, then repaired through the act of LSB embedding so that the stego image bears the statistics of the original cover. To protect against all orders up to some order $k$, the statistics of $n$-tuples must be preserved where $n$ is the least common multiple of all orders $\leq k$. We find that this is only feasible for securing against up to $3^{\rm rd}$-order attacks (Sample Pairs and Triples analyses) since higher-order protections result in virtually zero embedding capacities. Securing up to $3^{\rm rd}$-order requires redistribution of sextuplets: rather than perform these $6^{\rm th}$-order cover modifications, which result in tiny embedding capacities, we reduce the problem to the redistribution of triplets in a manner that also preserves the statistics of pairs. This is done by embedding into only certain pixels of each sextuplet, constraining the maximum embedding rate to be $\leq 2/3$ bits per channel. Testing on a variety of image formats, we report best performance for JPEG-compressed images with a mean maximum embedding rate undetectable by $2^{\rm nd}$- and $3^{\rm rd}$-order attacks of 0.21 bits per channel.
